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/*
* Copyright 2012 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkSurface_Base_DEFINED
#define SkSurface_Base_DEFINED
#include "SkSurface.h"
#include "SkCanvas.h"
class SkSurface_Base : public SkSurface {
public:
SkSurface_Base(int width, int height);
virtual ~SkSurface_Base();
/**
* Allocate a canvas that will draw into this surface. We will cache this
* canvas, to return the same object to the caller multiple times. We
* take ownership, and will call unref() on the canvas when we go out of
* scope.
*/
virtual SkCanvas* onNewCanvas() = 0;
virtual SkSurface* onNewSurface(const SkImage::Info&) = 0;
/**
* Allocate an SkImage that represents the current contents of the surface.
* This needs to be able to outlive the surface itself (if need be), and
* must faithfully represent the current contents, even if the surface
* is chaged after this calle (e.g. it is drawn to via its canvas).
*/
virtual SkImage* onNewImageSnapshot() = 0;
/**
* Default implementation:
*
* image = this->newImageSnapshot();
* if (image) {
* image->draw(canvas, ...);
* image->unref();
* }
*/
virtual void onDraw(SkCanvas*, SkScalar x, SkScalar y, const SkPaint*);
/**
* If the surface is about to change, we call this so that our subclass
* can optionally fork their backend (copy-on-write) in case it was
* being shared with the cachedImage.
*/
virtual void onCopyOnWrite(ContentChangeMode) = 0;
inline SkCanvas* getCachedCanvas();
inline SkImage* getCachedImage();
// called by SkSurface to compute a new genID
uint32_t newGenerationID();
private:
SkCanvas* fCachedCanvas;
SkImage* fCachedImage;
void aboutToDraw(ContentChangeMode mode);
friend class SkCanvas;
friend class SkSurface;
inline void installIntoCanvasForDirtyNotification();
typedef SkSurface INHERITED;
};
SkCanvas* SkSurface_Base::getCachedCanvas() {
if (NULL == fCachedCanvas) {
fCachedCanvas = this->onNewCanvas();
this->installIntoCanvasForDirtyNotification();
}
return fCachedCanvas;
}
SkImage* SkSurface_Base::getCachedImage() {
if (NULL == fCachedImage) {
fCachedImage = this->onNewImageSnapshot();
this->installIntoCanvasForDirtyNotification();
}
return fCachedImage;
}
void SkSurface_Base::installIntoCanvasForDirtyNotification() {
if (NULL != fCachedCanvas) {
fCachedCanvas->setSurfaceBase(this);
}
}
#endif
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